VIEW ARTICLE

Ecology and Epidemiology

Evaluation of Weeds and Plant Refuse as Potential Sources of Inoculum of Pseudomonas syringae in Bacterial Canker of Cherry. B. A. Latorre, Research associate, Department of Botany and Plant Pathology, Michigan State University, East Lansing, 48824, Present address of senior author: Departamento de Sanidad Vegetal, Facultad de Agronomia, Universidad de Chile, Casilla 1004, Santiago; A. L. Jones, professor, Department of Botany and Plant Pathology, Michigan State University, East Lansing, 48824. Phytopathology 69:1122-1125. Accepted for publication 25 April 1979. Copyright 1979 The American Phytopathological Society. DOI: 10.1094/Phyto-69-1122.

Pseudomonas syringae, which causes bacterial canker of sour cherry, was recovered from weeds and plant refuse collected under Montmorency sour cherry trees in three locations in Michigan. Isolates of P. syringae were recovered periodically from 7 May 1977 to 18 May 1978, while P. morsprunorum was recovered from only three of 54 weed samples and not from plant refuse. In greenhouse experiments, isolates of P. syringae from weeds and plant refuse were pathogenic to sour cherry leaves and shoots, peach seedlings, and sweet cherry fruit, and under wet conditions colonized and infected uninjured Montmorency sour cherry leaves. The potential of weeds and plant refuse as sources of inoculum for bacterial canker of cherry is discussed.